Railroads England - The Building Of The Rocket
( Originally Published 1927 )
A firm road had been constructed across Chat Moss and the tunnel at Liverpool had been finished, but the directors of the company had not yet decided what kind of tractive power should be used in working the railway. As they expected a large amount of traffic they gave over the idea of employing horse power, although that old-fashioned and conservative method had still some strong advocates. Some mechanical agency should be adopted; the question was whether that agency should be fixed or locomotive engines.
The discussion on this subject of tractive power brought many novel schemes to the consideration of the directors. Some promoters suggested plans for working the wagons by water power, others proposed hydrogen, and others carbonic acid gas. There were advocates of the employment of atmospheric pressure. Thomas Gray, of Nottingham, urged his plan of a greased road with cog rails ; and Vignolles and Ericsson recommended the use of a central friction rail, against which two horizontal rollers under the locomotive, pressing upon the sides of this rail, were to afford the means of ascending the inclined planes. Stephenson declared himself decidedly in favor of smooth rails and locomotive engines, which he was confident would be the most economical and convenient method of transportation.
The directors engaged various celebrated engineers to make reports on the advantages and disadvantages of the locomotive engine ; and most of these reports recommended the use of fixed rather than locomotive engines. Still Stephenson persisted in urging the latter method and promised that, if opportunity were given him, he would build an engine that would answer all requirements and prove cap-able of pulling heavy loads with speed, regularity, and safety. This persistence on his part had great weight with the directors, the more that they had seen him construct a road across Chat Moss, a work that had been declared impracticable by many engineers of the highest reputation. As he had succeeded there, he might also succeed with the locomotive.
Therefore, as an inducement to inventors to build locomotives, the directors offered a prize of £500 for the best locomotive engine that, on a certain day, should be produced on the railway and perform certain specified conditions in the most satisfactory manner.
These conditions were as follows:
1. The engine must effectually consume its own smoke.
2. The engine, if of six tons weight, must be able to draw after it, day by day, twenty tons weight (including the tender and watertank) at ten miles an hour, with a pressure of steam on the boiler not exceeding fifty pounds to the square inch.
3. The boiler must have two safety valves, neither of which must be fastened down, and one of them must be completely out of the control of the engine man.
4. The engine and boiler must be supported on springs, and rest on six wheels, the height of the whole not exceeding fifteen feet to the top of the chimney.
5. The engine, with water, must not weigh more than six tons ; but an engine of less weight would be preferred on its drawing a proportionate load be-hind it; if of only four and a half tons, then it might be put on only four wheels. The Company to be at liberty to test the boiler, etc., by a pressure of one hundred and fifty pounds to the square inch.
6. A mercurial gauge must be affixed to the machine, showing the steam pressure above forty-five pounds per square inch.
7. The engine must be delivered, complete and ready for trial, at the Liverpool end of the railway, not later than the first of October, 1829.
8. The price of the engine must not exceed £550.
As soon as this prize was offered George Stephenson set to work to capture it. His son Robert had been for some time engaged in mining in South America; in 1827 he had returned to England to take charge of the locomotive factory at Newcastle that had been established by his father and Edward Pease. There he proved himself a remarkably capable engineer and made many valuable additions to the construction of locomotives. With his father and other skilled workmen at the Newcastle plant he now built the engine, known as the "Rocket," for the Liverpool and Manchester competition.
The chief improvement over other locomotives that was made in the "Rocket" was the use of the multitubular boiler. Of this Robert Stephenson later said : "After the opening of the Stockton and Darlington, and before that of the Liverpool and Manchester Railway, my father directed his attention to various methods of increasing the evaporative power of the boiler of the locomotive engine. Amongst other attempts, he introduced tubes (as had before been done in other engines), small tubes containing water, by which the heating surface was materially increased. Two engines with such tubes were constructed for the St. Etienne Railway, in France, which was in process of construction in the year 1828; but the expedient was not successful—the tubes became furred with deposit, and burned out.
"Other engines, with boilers of a variety of construction, were made, all having in view the increase of the heating surface, as it then became obvious to my father that the speed of the engine could not be increased without increasing the evaporative power of the boiler. Increase of surface was in some cases obtained by inserting two tubes, each containing a separate fire, into the boiler; in other cases the same result was obtained by returning the same tube through the boiler ; but it was not until he was en-gaged in making some experiments, during the progress of the Liverpool and Manchester Railway, in conjunction with Mr. Henry Booth, the well-known secretary of the company, that any decided move-ment in this direction was effected, and that the present multitubular boiler assumed a practicable shape.
"At this stage of the locomotive engine, we have in the multitubular boiler the only important principle of construction introduced, in addition to those which my father had brought to bear at a very early age (between 1815 and 1821) on the Killingworth Colliery Railway. In the `Rocket' engine, the power of generating steam was prodigiously increased by the adoption of the multitubular system. Its efficiency was further augmented by narrowing the . orifice by which the waste steam escaped into the chimney; for by this means the velocity of the air in the chimney—or, in other words, the draught of the fire—was increased to an extent that far surpassed the expectations even of those who had been the authors of the combination."
The "Rocket" was constructed in the following fashion. The boiler was made cylindrical with flat ends, six feet in length, and three feet four inches in diameter. The upper half of the boiler was used as a reservoir for the steam and the lower half was filled with water. Through the lower part, twenty-five copper tubes of three inches diameter extended, which were open to the fire-box at one end and to the chimney at the other. The fire-box, or furnace, which was two feet wide and three feet high, was attached immediately behind the boiler, and was also surrounded with water. The cylinders of the engine were placed on each side of the boiler, in an oblique position, one end being nearly level with the top of the boiler at its after end, and the other pointing to-wards the centre of the foremost or driving pair of wheels, with which the connection was made from the piston-rod to a pin on the outside of the wheel. The engine, together with its load of water, weighed only four tons and a quarter, and was supported on four wheels, which were not coupled. The tender had four wheels also, and was similar in shape to a wagon; the front part of it held the fuel and the rear part a watercask.
When the "Rocket" was finished it was tried out on the Killingworth Railway and the new boiler construction was found to work perfectly. The engine was then sent by wagon to Carlisle and shipped from there to Liverpool.
The competition for the directors' prize was exciting the greatest interest, not only among engineers, inventors and mechanics but among the public generally, who felt that if this new method of trans-porting freight and passengers should be successful it would prove of immense benefit to the country at large. Crowds flocked to Rainhill, where the contest was to be held. Four engines were entered for the prize : the "Novelty," built by Braithwaite and Ericsson; the "Sanspareil," built by Timothy Hack-worth; the "Rocket," built by Stephenson and Booth; and Burstall's "Perseverance." Another engine, the "Cycloped," which was worked by a horse in a frame, had been entered, but was not allowed to compete. In addition to these, other engines were being constructed in different parts of the country, but could not be completed in time for the competition.
The place chosen for the contest was a level stretch of railroad about two miles in length. Each engine was to make twenty trips in the course of the day at a speed not less than ten miles an hour. To avoid confusion it was decided that the engines should be tried on different days.
The date fixed for the competition was October first, but this was changed to October sixth, and on that morning thousands of spectators journeyed to Rainhill, where a stand had been provided for the ladies and rows of carriages lined the road.
The "Rocket" was the first engine ready and the judges ordered it to make an experimental trip. On that day it ran about twelve miles in about fifty-three minutes. The "Novelty" next was tried. This was a very light locomotive, weighing only a little over three tons, of compact appearance, carrying water and fuel on the same wheels as the engine. Some question arose as to the load this locomotive should carry, and it only made an exhibition trip, during which it occasionally moved at the rate of twenty-four miles an hour. An exhibition trip was also made by the "Sans-pareil," a locomotive similar in pattern to those in use on the Stockton and Darlington Railway.
The competition was postponed to the following day. Then the bellows employed to create the blast in the "Novelty" would not work and that locomotive was withdrawn from the day's contest. There was also trouble with the boiler of the "Sans-pareil" and its builder was granted time to repair it. The crowd of spectators were disappointed and Stephen-son, to entertain them, brought out the "Rocket," and, attaching it to a coach holding thirty passengers, ran it along the line at a rate of from twenty-four to thirty miles an hour.
On October eighth the "Rocket" made her trial run. The engine was taken to the end of the line, the fire-box was filled with coke, the fire lighted, and the steam raised until it lifted the safety-valve to a pressure of fifty pounds to the square inch. The engine then set out, drawing about thirteen tons weight in wagons, and made ten round-trips along the two miles of road. The maximum velocity attained was twenty-nine miles an hour, and the average speed fifteen miles an hour. The spectators were astonished and delighted, and the directors of the company felt more than satisfied with Stephenson's achievement.
Neither the "Novelty" nor the "Sanspareil" was ready on that day, and when they were tested later neither was found so reliable as the "Rocket." The fourth engine, Burstall's "Perseverance," could not move at more than five or six miles an hour. The "Rocket" was the only locomotive that had fulfilled all the stipulated conditions, and its builders were accordingly awarded the prize.